Revert "iio: imu: Add support for Kionix KMX61 sensor"

The two halves of this part can run largely independently.  Hence
a version 4 of this patch followed that reorganized things completely.

This reverts commit d7d787d29148cde12958c2e3765ad3a55dc55eaf.

diff --cc drivers/iio/imu/Kconfig
Simple merge

diff --cc drivers/iio/imu/Makefile
Simple merge

diff --cc drivers/iio/imu/kmx61.c
Simple merge